1. Field of the Invention
The present invention relates to an ingot supplying apparatus for and an ingot supplying method of supplying a preheated magnesium ingot to a melting and holding furnace in which magnesium melt (in terms of a melt body of magnesium ingots) is held to be supplied to an injection sleeve of a die cast machine.
2. Description of Relevant Art
There have been disclosed in Japanese Patent Application Laying-Open Publication No. 2000-130958 such a type of magnesium ingot supplying apparatus and an associated magnesium ingot supplying method.
FIG. 1 shows the disclosed magnesium ingot supplying apparatus, which is generally designated by reference character 100 in the figure. The magnesium ingot supplying apparatus 100 has been proposed in consideration of various problems in an old art in which the ingot handling was performed by hands or in a relatively rough manner, such that a magnesium ingot laid on a supply guide, such as a roller conveyor, was simply pushed forward, for example by a cylinder, to the end, where it was thrown or fell directly into a pool of magnesium melt in a furnace, providing the melt with increased tendencies, for example, to be oxidized, lowered in temperature, and disturbed in level. The ingot supplying apparatus 100 has possibly suppressed such problems, in addition to an implemented automatic magnesium ingot supply leading to die cast products with an enhanced stable quality.
The ingot supplying apparatus 100 is roughly constituted with a preheater 2 for preheating magnesium ingots A, and an ingot supplier as an ingot supply mechanism 5 including an ingot chuck 4 for picking a preheated magnesium ingot A to be taken out of the preheater 2, carrying the picked ingot A to a position above magnesium melt M in a melting and holding furnace 3, and dipping and releasing the carried ingot A into the melt M, whereby this ingot A is supplied. The melting and holding furnace 3 inherently needs a periodical inspection, for example, once per three months. The periodical inspection requires a disconnection of the furnace 3 from a die cast machine 16, with the need of their reconnection after the inspection.
In FIG. 1, designated by reference character 6 is a magnetic hydraulic pump fitted on a goose-necked melt supply path of the furnace connected to the die cast machine; 7 is an ingot supply opening; 8 is a furnace top cover formed with the ingot supply opening; B is 4 surface level of the melt; 9 is a melt level detector; 10 is a float of the level detector; 11 is a sensing part of the level detector; and G is an antideflagrant gas filled over the melt for preventing deflagration of mnagnesium. The melting and holding furnace 3 is internally divided into an ingot melting chamber 12 (located at the right in the figure) and a melt holding chamber 13 (located at the left in the figure), by using a partition wall 15 separated for melt communication between the chambers 12 and 13.
The melting chamber 12 is covered by a right part of the top cover 8, where the ingot supply opening 7 is formed. The holding chamber 13 has, in a side wall thereof, a melt supply port 14 to be connected via the goose-necked supply path to the die cast machine 16. The ingot supply opening 7 is thus distant from the melt supply port 14, which means a difficulty for the opening 7 to well recover an original position after the inspection that needs a reconnection of melt supply path which tends to accompany a positional error. To this point, the ingot supply mechanism 5 has a support post 18 that provides a horizontal arm for slidably supporting a vertical feed screw, which carries the ingot chuck 4. The support post 18 is fixed in position and serves as a reference of the ingot supply mechanism 5. This mechanism 5 is a separate installation relative to the furnace 3. Accordingly, chuck operating parts of the ingot supply mechanism 5 need to be centered to the ingot supply opening 7 after every inspection, thus resulting in a reduced working efficiency, yet leading to a reduced production efficiency.
Further, a chuck part 4a of the ingot chuck 4 keeps holding a magnesium ingot A until the most part of the ingot A gets dipped in the magnesium melt M. Therefore, not simply the chuck part 4a, but also a driving part 4b directly linked to the chuck part 4a is exposed to an atmosphere as hot as approx. 400xc2x0 C., so that an entirety of the ingot chuck 4 suffers a reduced durability.
Still more, the ingot supplying apparatus 100, in which ingots A need to stand upright to be heated in the preheater 2, has an ingot carrier 17 adapted to hold the ingots A standing with their longitudinal axis upright, in addition to other considerations, with significant complexity resulting in high cost.
The present invention has been made with such points in view. It therefore is an object of the present invention to provide an ingot supplying apparatus and an ingot supplying method, which are free from centering an ingot supplying implement to an ingot supply opening upon reconnection of a melting and holding furnace to a die cast machine, such as after inspection, thus achieving an increased production efficiency, and which additionally allow for an ingot handling implement to have an increased durability, and for a preheater to be simplified in structure with a reduced cost.
To achieve the object, according an aspect of the invention, there is provided an ingot supplying apparatus for supplying a preheated magnesium ingot from a preheater to a melting and holding furnace, the apparatus comprising: an ingot supply opening provided to a furnace cover of the melting and holding furnace and with a shutter operable to open and close by an external signal; an intermediate handler having a receiving case configured substantially in a channel shape open at both ends thereof, and pivoted on the furnace cover to be movable between a substantially horizontal lying position with one end thereof coincident with an ingot exit of the preheater to allow for a preheated ingot to be forward therein in a lying position with a longitudinal axis thereof set substantially horizontal and a substantially vertical standing position with the other end thereof coincident with the ingot supply opening to bring a distal end of the preheated ingot forwarded therein into abutment with the shutter to make the preheated ingot stand thereon; and an ingot supplier having a pawl chuck configured to enter inside the receiving case from an open side of the receiving case in the substantially vertical standing position, to be pressed against a rear end part of the preheated ingot as accommodated, and attached to, for a vertically guiding by, a drive mechanism fixed at a base end thereof to the furnace cover, and adapted for the shutter to be opened and the pawl chuck to be lowered to supply the preheated ingot into the melding and holding furnace.
According to another aspect of the invention, there is provided an ingot supply method using an ingot supplying apparatus according to the previous aspect, wherein a magnesium ingot is set in a substantially horizontal lying position with a longitudinal axis thereof substantially horizontal, preheated in the preheater, and thereafter forwarded, with the lying position maintained, via the ingot exit of the preheater, into the receiving case of the intermediate handler in the substantially horizontal lying position, and thereafter is placed, by having the receiving case set in the substantially vertical standing position, on the shutter, in a vertical position with a distal end thereof on the shutter, and held by the pawl chuck of the ingot supplier pressed against a rear end part thereof, and thereafter, with the shutter opened, is dipped in respect of a most part thereof, by a vertical lowering movement of the pawl chuck at a low speed, into a magnesium melt in the melding and holding furnace, before a release thereof for supply.